The present invention relates to a fuel cylinder attaching structure in a motorcar running by a gas fuel such as natural gas.
A fuel cylinder or tank to be mounted on a natural gas vehicle is one such as a light weight aluminum liner tank or non-metallic liner tank which is expanded and deformed when filled with the fuel.
As a method for mounting and fixing such a fuel cylinder which expands and contracts itself onto a vehicle, a practice to fasten the fuel cylinder by a fixing band with spring is known. FIGS. 4 and 5 show rough construction of the fixing band.
A fixing band 01 shown in FIG. 4 is formed in a circular having both ends 01a, 01b positioned at an upper part and a central lower part fixed to a car-body. At the both ends 01a, 01b are fixed stays 02a, 02b opposite to each other and a clamp bolt 03 penetrates the stays 02a, 02b interposing a spring 05 between the bolt and the stay. A nut 04 is engaged with the bolt 03 to clamp the stays 02a, 02b.
Since the stays are clamped through the spring 05, even if the fuel cylinder expand or contract, the diameter of the fixing band changes flexibly by elastic deformation of the spring 05 to follow the deformation of the fuel cylinder so that the fuel cylinder can be fixed by clamping force of the spring 05 acting always.
In FIG. 5, a fixing band is divided into an upper fixing band section 010 and a lower fixing band section 011, and a central lower part of the lower fixing band section is fixed to the car-body. A stay 010a at an end of the upper fixing band section 010 and a stay 011a at an end of the lower fixing band section 011 are clamped by a bolt 012a and a nut 013a through a spring 014a, and a stay 010b at another end of the upper fixing band section 010 and a stay 011b at another end of the lower fixing band section 011 are clamped by a bolt 012b and a nut 013b through a spring 014b.
In each of the above both cases, the fixing band 01 (011) is fixed at one spot 01c (011c) to make the diameter change of the fixing band uniform for pertinently coping with the expansive deformation of the fuel cylinder.
However, according to the above fixing band fixed to the car-body at one spot, though it is possible to cope with the expansive deformation of the fuel cylinder, it is difficult to fix the fuel cylinder surely against vibration and other forces given to the fuel cylinder.
Heretofore, a fuel cylinder supporting structure having a pair of front and rear supporting frames fixed with respective fixing bands is known, but this structure is one for a fuel cylinder expanding little and therefore a clamp with spring is not used in the structure.